Search Keyword Tools

• Google AdWords Keyword Tool – Google’s own keyword research tool, the GAKT was developed to help paid search advertisers, but is also used routinely by SEO’s.
• Google Insights – Check out when a keyword is most seached. Helpful for choosing keywords for seasonal campaigns.
• Also see SEMrush below… I rely on this tool for some good competitive research.

Social Media Tools

• Crowdbooster – Awesome tool for Twitter marketing.  Comes with recommendations on who to engage with, and analytics into how your messages and follower growth is trending.
• Shared Count – Enter a URL, get the Facebook, +1, Twitter, LinkedIn, Digg, and Buzz social metrics.
• – Like Google Insights for blogs. Tracks URLs or keywords.

Analytics

• Google Analytics – The hero of free analytics.  Some interpolated data, but a pretty robust interface.  Segmentation and goal funnels are available.  You can’t correlate as deeply as something like Omniture (arguably better suited for enterprise sites), but for SEO and marketing, this will likely serve the purpose just fine.
• Woopra – Real time analytics.  Provides a nice view into live queries and active pages.  Plus it’s just fun to watch your visitors navigate your site. The pay version gives you filters and navigation path.  For certain strategies, I hang out here more than GA.  It’s great ‘in your face’ insight.

Domain Searchers

• DD Whois – When you’re looking for a domain, this is a quick iPhone friendly way to check for availability.

Technical Audits

• URI Valet – Scans a page for headers, tag content, content density, objects, external links, and speed.
• WooRank – Also scans a page for a quick summary of traffic estimations, site rank, popular pages, tags, and more. (Thanks Brian)
• Robots.txt Checker – I like this one because it also gives some warnings and insight.

Comparison Tools

• – Archive.org has snapshots of decades old websites. Nice if you have a need to see competitor changes, or have a client who’s content or URLs suddenly disappeared.
• SEMrush – You only get a little for free here (you pay to unlock the full beast), but this tool is great for giving you insight into what your competitors are bidding and organically ranking for. This is one of my favorites.
• Paid Link Discovery Tool – Read the post, and copy the worksheet.  It’s a clever tool to help identify potential paid link buyers… but you have to continue doing some digging on the resulting suspects.  You can get some false positives.  Still, very useful.

Counters / Measures

• Keyword Density Tool – For those who still think in terms of keyword density, you’ll find this useful.

Text Spinners

• Free Article Spinner – This tool will take your content and rewrite it using other synonyms. Does the spun copy read well? No. But if you’re using an auto-spinner, you probably don’t care about that.

URL Builder

• Google Analytics URL Builder – Simple tool to help you whip up tracking parameters for your URLs.

URL Helpers

• URL Opener – When you have a list of URLs, and want to open them in tabs, this quick web-based tool can handle the job.

Emulators

• – This is an emulator that attempts to show you what a search engine spider sees. Feels pretty accurate to me.

Browser Extensions

Tab Helpers

• Send Tabs URL (firefox) – When doing link building, you start to open a lot of tabs. How many times do you wish you could just get them in a document to follow up on later? Now you can.
• Multi Links (firefox) – This tool lets you highlight a large group of links (in the SERPs or webpage), and attempts to open all of them for you at once. Can be a time saver in certain applications.
• SEO Serp (chrome) – Unlike many, I’m not a fan of Firefox’s rank checker. I find it much too slow and innacurate. Instead I opt for SEO Serp for chrome.
• Web Developer (firefox) (chrome) – This is a must. Need to see the site with javascript, images, or CSS disabled? Click it off with this plugin. It does more, so get this bad boy.
• Firebug (firefox) (chrome) – Another must. This tool lets you edit code live on a page, and troubleshoot. Once you get your head around how it works, you’ll be using this all the time to inspect code.